Yes. Hamsters from the same litter can ALWAYS mate with each other as long as they're at least 4 weeks old.
no
yes. all hamsters either fight or have babies together even if they were in the same litter!
Nope. So long as it is a hamster.
Yes.
Depends on what you mean by "can". Physically they certainly can, but they shouldn't be allowed to. If they have the same parents it doesn't matter if they're from different litters, they're still brother and sister. And breeding from such close relatives just isn't healthy.
They will do both. Both. They will first mate, and then the female will kill the male.
it's quite rare, or impossible
Yes they can... but there is even some chances that they don't....
The same as a cat that has never had a litter of kittens, only much smaller. The color depends on the color of the fur.
No, Short-Haired Syrian hamsters and Panda Bear hamsters belong to different species and cannot mate with each other. Interbreeding between different species of hamsters is not recommended due to potential health risks and genetic complications. It is best to keep hamsters of the same species together for breeding.
'Teddybear' and 'Longhaired' are just names of different varieties of Syrian (Golden) Hamsters. Their only difference is their fur length, and in fact most people would consider those two to be the same thing. Regardless, since both are Syrian Hamsters and therefore the same species, they can mate.
Compatible with humans.. or compatible with other dwarf hamsters? I've had two dwarf hamsters and they were great pets. A litte more work then syrians but they were great pets. I had two from the same litter, then soon found out I had to put them in separate cages because they fought a lot.. so no, I don't think Russian (especially) dwarf hamsters are compatible - even if they came from the same litter. They also may be fine in the beginning but sooner or later one becomes the 'runt' and the fighting begins.